Terminal blocks for use in electrical circuits



April 9, 1968 G. F. W. POWELL ET AL TERMINAL BLOCKS FOR USE IN ELECTRICAL CIRCUITS Filed May 5, 1966 Mam wmw .cM MLM United States Patent 3,377,614 TERMINAL BLOCKS FOR USE IN ELECTRICAL CIRCUITS Gordon Francis Wellington Powell, Deptford, London, and Stephen Geoffrey Hinton, Seaford, England, assignors to Molins Machine Company Limited, London, England, a corporation of Great Britain Filed May 5, 1966, Ser. No. 547,861 Claims priority, application Great Britain, May 6, 1965, 19,168/ 65 2 Claims. (Cl. 339-198) ABSTRACT OF THE DISCLOSURE A terminal block is described comprising a plurality of insulating blocks which are slidably assembled and secured to a base member. Opposite faces of each insulating block include corresponding projections and recesses such that each projection on one face of one block fits into a recess on the face of the contiguous block. There are further recesses in opposite faces of the blocks for locating in position the metal electrical contacts between adjacent blocks. The terminal block is provided with an end block at each end of the row of insulating blocks, means being provided for securing the insulating blocks and end blocks together.

This invention concerns improvements in terminal blocks for use in electrical circuits.

An object of the invention is to provide a terminal block consisting of a number of like parts carrying contacts, which can be assembled into a rigid block of any desired length.

According to the invention there is provided a terminal block comprising insulating blocks shaped to assemble together in a line and to house metal contacts between each pair of blocks, the blocks having bases shaped to enter a channel formed in a base member only by endwise movement into and along said channel, and means for locking the blocks in position in said channel.

The base member which may have two side webs and a base web is preferably shaped to provide a channel of dovetail shape in cross-section with the broad end at the base web of the channel and in such case each insulating block has its bottom part formed as a lug of dovetail shape and of a size to be a sliding fit in the channel of the base member.

End blocks provided with separate dovetail shaped keys may provide the means for locking the insulating blocks in position, the end blocks being shaped to embrace the side webs of the base member and the keys being fixed to the end blocks by screws which, when tightened, clamp the side webs of the base between the keys and the end blocks.

The insulating blocks may be grooved or recessed on the faces which adjoin neighbouring blocks when the terminal block is assembled and extending downwards to the base member and have slits in said faces at right angles to the grooves and in which contact strips fit and are held, the grooves being provided to accommodate limbs extending at right angles to said contact strips whereby a contact strip is blocked against movement when the parts are assembled.

In a preferred construction a metal contact comprises two or more spaced parallel contact strips joined by a limb extending at right angles to said strips. The number of strips depends on requirements but three parallel strips, which provide six ends or tags is a useful number and in this case the limbs joining neighbouring strips are joined thereto at opposite edges so that, viewed endwise, a contact is of S shape, the limbs of the S being substantialy straight.

The invention will be described in more detail with reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of a complete terminal block, the middle part being broken away,

FIGURE 2 is a perspective view of a metal contact as used in the block of FIGURE 1,

FIGURE 3 is a perspective view of a known kind of connector for attaching leads to the tags of the contact shown in FIGURE 2,

FIGURE 4 is a front elevation of an end block illustrated in FIGURE 1 but showing the face which is hidden in FIGURE 1,

FIGURES 5, 6 and 7 are a front elevation, side elevation and a section taken on line 7-7 of FIGURE 5, respectively, of an insulating block shown in FIGURE 1 and in which the metal contacts shown in FIGURE 2 are supported.

The invention will be first briefly described with reference to FIGURE 1. Referring to FIGURE 1 the terminal block assembly comprises a base 1 having a channel 2 of dovetail shape in which other components are fitted. As shown in full lines the channel has slots 3 in its base web where-by it may be fixed to any structure by screws such as the one marked 4. Alternatively the base 1 may have exterior webs 5, slotted for screws, all as indicated by broken lines.

Insulating blocks 6 having dovetail shaped tongues or lugs 14 are slid into the channel after metal contacts 7 have been assembled with the blocks and the blocks are closed up and held by end blocks 8, which may be of metal, these blocks being locked in position by dovetail shaped keys 9 pulled tightly against the side webs of the channel 2 by screws 10. Connections may then be made to any contact by means of a connector shown at 11, FIGURE 3, these connectors being known commercial articles.

Referring now to FIGURES 5 to blocks such as polycarbonate. On the faces of each block which adjoin similar faces of the neighbouring blocks are dowels 12 and holes 13, the dowels and holes respectively being oppositely disposed on the two faces of the block so that the dowels on one block will fit in the holes of the next block. The top of the block is recessed at 15 so that an indicator strip 16, FIGURE 1, may be slid in. The block is also recessed in its front and back faces at 17 and slit at 18 to accommodate the metal contacts 7. Outstanding ribs 26 on the blocks 6 isolate the contacts between neighbouring blocks.

Referring now to FIGURE 7 it will be seen that if the metal contact is viewed in the direction of arrow A it is of S shape in appearance with the limbs of the S formed by substantially straight lines. The tags 19 of the contact are housed in the slits 18 of neighbouring faces of the blocks 6 while the central portion, which is of S form as mentioned above, is housed in the recesses 17 of two neighbouring blocks. Small holes 20 are made in the ends of the tags in case it is desired to solder a wire to any tag.

Referring now to FIGURE 4 the face of the block 8 which will engage the face of an insulating block has a central upstanding lug 21 which fits in a recess 17 of a block 6 and it also has two blind holes 22 to go over the dowels 12 of said insulating block.

The connector 11 shown in FIGURE 3 which, as aforesaid, is known, is made of springy brass and consists of an end 23 which is clinched over the end of a wire 24 in the usual way while the part which fits on a tag has two turned over parts 25 and beneath them the base of the connector is embossed upwards in the form of two parallel 7 the insulating 6 are moulded from suitable insulating material indentations each substantially beneath the middle of the curve of the corresponding turned over part so that the tag is very firmly gripped when the connector is pushed on to 11;.

Thus, as so far described each contact will provide three leads in and three out but if for any reason it is undesirable that a complete contact should be fitted between a pair of blocks -6 one or more of the tags can be omitted, or clipped off, so that there can be one lead in and one out, two leads in and two out or any combination within the limit of six tags. However a portion or portions of the vertical limbs of the S are left wherever possible so that the contact is firmly held and located.

It is possible to arrange to check circuits by a test prod if the indicating strip is slid out as the recesses 17 may if desired be extended to the top surface of the blocks 6, immediately below the indicating strip.

The invention provides a terminal block with push-on terminals for small tags and is particularly useful for'low voltage transistor work, nothing suitable being commercially available. The metal contacts being integral with several tags provided a superior arrangement to the double contacts used in larger blocks where additional tags are riveted on.

What we claim as our invention and desire to secure by Letters Patent is:

1. A terminal block comprising a base member, a plurality of insulating blocks, means securing said insulating blocks to said base member, opposite faces of each insulating block including corresponding projections and recesses such that each projection of one face of one block fits into a recess on the face of a contiguous block locking adjacent blocks against relative movement therebetween when secured to said base member, further recesses in said opposite faces of each insulating block, and metal contacts retained in said further recesses between contiguous insulating blocks, said means for securing said insulating blocks to said base member comprising a channel in said base member, said channel being of dovetail shape in cross-section having side webs with the broad end of the dovetail on the side of said base remote from said insulating blocks, said insulating blocks 5 each having a base shaped to enter said channel only by movement endwise of said channel, end blocks shaped to embrace the base member, separate dovetail-shaped keys shaped to fit within the channel, and screws securing said keys to said end blocks to clamp said side webs therebetween.

2. A terminal block comprising a base member, a plurality of insulating blocks, means securing said insulating blocks to said base member, opposite faces of each insulating block including corresponding projections and recesses such that each projection of one face of one block fits into a recess on the face of a contiguous block locking adjacent blocks against relative movement therebetween when secured to said base member, further recesses in said opposite faces of each insulating block, and metal 2 contacts retained in said further recesses between contiguous insulating blocks, each of said metal contacts comprising at least two spaced parallel contact strips joined by limbs extending at right angles to said strips and wherein said further recesses for receiving said metal contact comprises slits in said blocks corresponding to said parallel contact strips and grooves for receiving said limbs.

References Cited UNITED STATES PATENTS 2,922,139 1/1960 Ustin 339198 3,201,747 8/1965 Blanchet 339-198 3,018,464 1/1962 Mrenna et a1 339-198 3,296,576 1/1967 Motten; 339-198 MARVIN A. CHAMPION, Primary Examiner.

FRANCIS K. ZUGEL, Examiner.

R. S. STROBEL, Assistant Examiner. 

